PROJECT SUMMARY/ABSTRACT Trauma is a common, high-risk, and high-cost condition that uniquely affects the health of older adults. In 2017 alone, 4.8 million non-fatal traumatic injuries were reported among older adults aged ?65 years in the United States (US), costing hospitals and payers upwards of $66.8 billion (2019 USD) or ~2% of all US spending on healthcare. By 2050, the number of older adults is projected to rise to 89 million (22.1% of the total US population). With it is expected to come a parallel increase in the number of older adult trauma patients. Traumatic brain injury (TBI) and hip fracture are among the most common and debilitating forms of trauma encountered among older adults, often resulting in long-term functional impairments, nursing home admission, decreased independence, and shortened life expectancy. Improving outcomes for older trauma patients, particularly those with severe TBI and hip fracture, is an important national priority. While external benchmarking has evolved as the preeminent methodology used to compare hospital outcomes when measuring quality of care, its application among trauma patients is currently limited by a lack of available post-discharge data and concerns within the trauma community that poorly applied metrics might not be representative of the complex patients that trauma providers treat and the breadth of adverse outcomes that trauma patients face. Through this grant and its three specific aims, we propose to build on existing efforts within trauma to benchmark hospitals. Expanding on data currently limited to in-hospital mortality, we will utilize longitudinal 100% Medicare fee-for-service claims to study post-discharge outcomes among older adults hospitalized for: 1) trauma in general, 2) severe TBI, and 3) hip fracture. Aim 1. To quantify the extent of variability in and potential discordance between trauma mortality and readmission performance profiles. Aim 2. To ascertain whether there are clusters of hospitals with highly similar and/or highly divergent trauma readmission and mortality outcomes and identify associated factors. Aim 3. To compare the results of conventional external benchmarking for readmission with those attained under a model that allows for competing risk. The findings from this work will lay a foundation on which the continued development of trauma quality improvement and national health policy benchmarking can build. It will have a major, direct impact on how the quality of care for older adults is measured and conceptualized, helping to determine the future of clinical care for one of the most common, high-risk, and high-cost conditions affecting the health of older adults while simultaneously informing the development of meaningful and strong quality metric models with applications to both trauma and other non-trauma conditions.